Electrical motors are generally classified as alternating-current (a-c) motors or direct-current (d-c) motors. In either classification the motors are designed to receive electrical energy and convert that energy into mechanical energy, also referred to as “torque”. A-c motors are used more often than d-c motors because of the availability of a-c power over d-c power. All motors however, sustain energy losses in converting the electrical energy to the mechanical energy. This loss is due to bearing friction, cogging, the resistance loss that occurs by current flowing through the conductors of the motor armature, the electrical field and core losses that are due to hysteresis and eddy currents. These losses can contribute to a non-smooth rotation, the production of heat and lower efficiency.
Prior art motors utilize laminated metal stators that have wire windings which are wound perpendicular to the longitudinal axis of the rotor. The windings produce the magnetic force that pushes or pulls against a set of magnets which are located around the rotor of the motor. In contrast, the inventive brushless a-c motor utilizes a stator that is made of a non-conductive material such as plastic and a metal rotor that rotates around the stator to produce a rotational force. The non-conductive stator has wire windings that are wound parallel to the longitudinal axis of the stator. The rotational force is produced when current flows through the wires. The combination of the non-conductive stator, the permanent magnets in the rotor and the novel wire winding eliminates or at least minimizes the problems listed above for the prior art motors. Additionally, the inventive design provides a high efficiency electrical energy converter.
A search of the prior art did not disclose any literature or patents that read directly on the claims of the instant invention. However, the following U.S. patents are considered related:
PATENT NO.INVENTORISSUED7,183,686Sasaki et al27 Feb. 20077,183,684Miyashita27 Feb. 20075,894,183Borchert13 Apr. 19984,393,320Anderson12 Jul. 1983
The U.S. Pat. No. 7,183,686 discloses a synchronous motor that includes a stator, a rotor and permanent magnets. The rotor includes a rotor iron core that rotates relative to the stator, and a plurality of conductor bars accommodated within corresponding slots in the rotor iron core. The conductor bars have opposite ends that are short circuited by respective short circuit rings to form a starter cage conductor. The rotor also has a plurality of magnet retaining slots located on an inner side of the conductor bars, in which permanent magnets are embedded.
The U.S. Pat. No. 7,183,684 discloses a permanent magnet rotary motor that can maintain a higher torque density and reduce cogging torque when compared to a conventional permanent magnet rotary motor. A pair of end surfaces from each permanent magnet is used for a rotor that is placed substantially parallel to a virtual plane. The virtual plane extends in the radial direction of a rotor core while passing through the centers of a stator core.
The U.S. Pat. No. 5,894,183 discloses a permanent magnet rotor for an electric generator or motor having a core lamination hub formed from a stack of round plates. The plates have peripheral slots for holding the first end of a rectangular magnet. Each magnet has an outer end which is held by a slotted pole piece formed from laminated plates. A first and a second side plate overlie each side of the lamination hub, the magnets and the pole pieces. Fasteners are passed through holes in the side plates, hub plates and pole pieces to form a rigid rotor.
The U.S. Pat. No. 4,393,320 discloses a permanent magnet rotor comprising a housing defining a central rotor axis and an inner ring secured within the housing. Annularly extending around the rotor axis is a plurality of permanent magnets that are annularly spaced around the inner ring. An outer ring is secured within the housing and annularly extending around the permanent magnets are a plurality of outer ring segments. The rotor has a filler material that fills the spaces between adjacent permanent magnets and adjacent the outer ring segments.
For background purposes and as indicative of the art to which the invention is related, reference may be made to the following remaining patents located in the search:
PATENT NO.INVENTORISSUED7,262,526Shiga, et al28 Aug. 20077,233,092Murakami, et al19 Jun. 20076,984,908Rinholm, et al10 Jan. 2006